1. Field of the Invention
The present invention relates generally to heat exchangers and, more specifically, to a continuous corrugated heat exchanger and method of making same for a motor vehicle.
2. Description of the Related Art
It is known to provide a folded or corrugated plate heat exchanger such as an oil cooler in a motor vehicle. Typically, the heat exchanger has a plurality of elongated plates that are joined together to define a plurality of fluid passageways therethrough. Each of the passageways is formed between inwardly facing surfaces of a joined pair of mating plates. The interiors of these joined mating plates define fluid passageways through which a first fluid medium to be cooled may flow. The heat exchangers also include conductive fins disposed between adjacent pairs of mating plates to enhance the heat exchange between the fluid flowing through the fluid passageways thereof while a second fluid medium contacts an exterior thereof. Typically, the first fluid medium is oil and the second fluid medium is air. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the plates.
Typically, folded plate heat exchangers are manufactured by stacking individual plates together to form a plurality of adjacent pairs, then interleaving the pairs of mating plates with conductive fins to form a stacked plate structure. End plates are then placed at opposite ends of the stacked plate structure to form a heat exchanger core. The assembled heat exchanger core is then brazed in a furnace to complete the manufacturing process. This is an extremely labor intensive process requiring human assemblers to physically stack the individual plates with each other to form the heat exchanger core prior to being brazed.
One proposed method, which may increase the productivity in fabricating corrugated heat exchangers, are disclosed in U.S. Pat. Nos. 5,734,460 and 5,855,240. These patents disclose a method of making a heat exchanger wherein a plurality of individual plates are stamped from a single sheet of material and inter-linked together by tab members. Each tab member is a straight piece of metal material that connects the plates and provides a location for bending to occur. After being formed, the plates are folded in a zig-zag formation to form a heat exchanger core. Each core has end sheets to seal off the core and provide a structure to which inlet and outlet tubes can be brazed, and to provide damage protection to the core. These end sheets, two per core, are stamped out separately, in a unique end sheet die, then manually assembled to the core. The end sheets are stamped out of 0.060 inches thick material, which is different than the core material thickness of 0.0195 inches.
Although the above heat exchangers have worked well, it is desirable to eliminate the use of separate end sheets for the stacked refrigerant plates of the heat exchanger. It is also desirable to provide a continuous corrugated laminated end sheet for a heat exchanger. It is further desirable to provide a continuous corrugated heat exchanger and method of making same.
Accordingly, the present invention is a continuous corrugated heat exchanger including a plurality of contiguous plates and a plurality of tabs disposed between and joined to adjacent plates. The plates include a plurality of refrigerant plates having a plurality of beads and at least one blank sheet at each end of the refrigerant plates forming an end sheet. The refrigerant plates are folded bellows-like to form a stack and the end sheet is folded on a top and bottom of the stack.
Also, the present invention is a method of making a continuous corrugated heat exchanger. The method includes the steps of stamping a plurality of contiguous refrigerant plates joined together by a plurality of tabs and stamping at least a first and last one of the refrigerant plates flat to form an end sheet. The method also includes the step of bending the refrigerant plates to form a stack and bending the end sheets over the refrigerant plates at a top and bottom of the stack.
One advantage of the present invention is that a continuous corrugated heat exchanger such as an oil cooler is provided for a motor vehicle for cooling liquid oil. Another advantage of the present invention is that the continuous corrugated heat exchanger has continuous corrugated laminated end sheets for the stacked plate structure of the heat exchanger core. Yet another advantage of the present invention is that the continuous corrugated heat exchanger uses regular refrigerant plates as end sheets, stamping out a complete heat exchanger core. Still another advantage of the present invention is that the continuous corrugated heat exchanger has higher strength, much simpler manufacturing, higher quality and lower cost.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.